I’ve seen many different recommendations, but what I like- go slow. Start with 5 grams and over about 2 weeks gradually increase to about 30 grams. Then gradually decrease. How long you need to take it depends on you. Probably 1-4 months for healing leaky gut. But just pay attention to your symptoms. If your digestion and eczema have improved, then start tapering it down. You can always continue to take it as maintenance to keep your intestinal lining strong.
